The present invention relates to a process for producing a polyphenylene sulfide multifilament yarn, a polyphenylene sulfide multifilament yarn and the use of a polyphenylene sulfide multifilament yarn.
The term “filament” as used herein means fibers of practically endless length. Yarns consisting of a number of filaments are therefore called filament yarns.
Polyphenylene sulfide filaments are available as monofilament yarns, multifilament yarns or staple fibers. Polyphenylene sulfide filaments are produced by a melt spinning process. They may be used at temperatures up to 190° C. without showing significant damage or degradation. PPS filaments are flame resistant, self-extinguishing and melt at temperatures of about 285° C.
DE 40 06 397 pertains to a process for production of mono- and multifilaments as well as staple fibers made of polyphenylene sulfide. The process is a melt spun process. Below the spinneret air or inert gas with a temperature between 50° C. and 150° C. is blown against the filaments followed by multiple stage drawing to a total draw ratio of 3.7 to 11.2. The process may yield a multifilament yarn with a tenacity of 76 cN/tex and elongation at break of 16%
Japanese Patent Application No. 3-168750 discloses a method for manufacturing polyphenylene sulfide fibers in a melt spun process. Polyphenylene sulfide is melted and spun through a spinneret whereupon the spun yarn is cooled by blowing a cooling air flow with a temperature of at least 45° C. onto same. The yarn is then hot drawn by passing through a heating zone.
Japanese Patent Application No. 9-78693 discloses polyphenylene sulfide fibers for electrical insulation, method of manufacturing the same, and electrical insulation material. The tenacity of the melt spun and drawn fibers lies at 44 cN/tex, elongation at break lies around 20%. Polyphenylene sulfide is spun by a spinneret, the spun thread is passed through a high temperature atmosphere surrounded by a heating tube of 5 cm to 30 cm length at a temperature between 280° C. and 350° C., after which it is solidified by cooling uniformly by air at 100° C. or less, preferably 20-80° C. This undrawn yarn is fed continuously to the heat drawing process and normally is drawn in a plurality of stages of 2 stages or more, without being wound off. The draw ratio should be 3.0-5.5.
Japanese Patent Application No. 2-219475 discloses polyphenylene sulfide fibers and method of manufacturing same. The polyphenylene sulfide fibers consisting of a continuous filament having a tenacity of at least 44 cN/tex and elongation at break of at least 20%. For the process pellets of polyphenylene sulfide fiber polymer are melted at a temperature of 310-340° C. and passed successively through a filter and spinneret holes of 0.1-0.5 mm diameter to form a spun thread strand, which is subsequently passed through a high-temperature atmosphere enclosed by a heat insulating tube or a heating tube disposed over a distance of 5-30 cm immediately below the spinneret in which said spinneret holes are formed and controlled to an ambient temperature of 150-350° C., and then cooled by a warm air flow or cool air flow at 100° C. or below.